private static KeyBlobMagicNumber EcdhCurveNameToMagicNumber(string name, bool includePrivateParameters)
{
switch (CngKey.EcdhCurveNameToAlgorithm(name).Algorithm)
{
case AlgorithmName.ECDHP256:
return(includePrivateParameters ?
KeyBlobMagicNumber.BCRYPT_ECDH_PRIVATE_P256_MAGIC :
KeyBlobMagicNumber.BCRYPT_ECDH_PUBLIC_P256_MAGIC);
case AlgorithmName.ECDHP384:
return(includePrivateParameters ?
KeyBlobMagicNumber.BCRYPT_ECDH_PRIVATE_P384_MAGIC :
KeyBlobMagicNumber.BCRYPT_ECDH_PUBLIC_P384_MAGIC);
case AlgorithmName.ECDHP521:
return(includePrivateParameters ?
KeyBlobMagicNumber.BCRYPT_ECDH_PRIVATE_P521_MAGIC :
KeyBlobMagicNumber.BCRYPT_ECDH_PUBLIC_P521_MAGIC);
default:
// all other curves are new in Win10 so use named curves
return(includePrivateParameters ?
KeyBlobMagicNumber.BCRYPT_ECDH_PRIVATE_GENERIC_MAGIC :
KeyBlobMagicNumber.BCRYPT_ECDH_PUBLIC_GENERIC_MAGIC);
}
}
public override void GenerateKey(ECCurve curve)
{
curve.Validate();
_core.DisposeKey();
if (curve.IsNamed)
{
if (string.IsNullOrEmpty(curve.Oid.FriendlyName))
{
throw new PlatformNotSupportedException(string.Format(SR.Cryptography_InvalidCurveOid, curve.Oid.Value));
}
// Map curve name to algorithm to support pre-Win10 curves
CngAlgorithm alg = CngKey.EcdhCurveNameToAlgorithm(curve.Oid.FriendlyName);
if (CngKey.IsECNamedCurve(alg.Algorithm))
{
CngKey key = _core.GetOrGenerateKey(curve);
ForceSetKeySize(key.KeySize);
}
else
{
int keySize = 0;
// Get the proper KeySize from algorithm name
if (alg == CngAlgorithm.ECDiffieHellmanP256)
{
keySize = 256;
}
else if (alg == CngAlgorithm.ECDiffieHellmanP384)
{
keySize = 384;
}
else if (alg == CngAlgorithm.ECDiffieHellmanP521)
{
keySize = 521;
}
else
{
Debug.Fail(string.Format("Unknown algorithm {0}", alg.ToString()));
throw new ArgumentException(SR.Cryptography_InvalidKeySize);
}
CngKey key = _core.GetOrGenerateKey(keySize, alg);
ForceSetKeySize(keySize);
}
}
else if (curve.IsExplicit)
{
CngKey key = _core.GetOrGenerateKey(curve);
ForceSetKeySize(key.KeySize);
}
else
{
throw new PlatformNotSupportedException(string.Format(SR.Cryptography_CurveNotSupported, curve.CurveType.ToString()));
}
}
public override void GenerateKey(ECCurve curve)
{
curve.Validate();
if (m_key != null)
{
m_key.Dispose();
m_key = null;
}
CngKey newKey = CngKey.Create(curve, name => CngKey.EcdhCurveNameToAlgorithm(name));
m_key = newKey;
KeySizeValue = newKey.KeySize;
}